This project will investigate the chemical reaction of aromatic nitroso compounds with analogs of thiamine. Such a reaction will lead to the formation of hydroxamic acids, which are often times potent carcinogens. This project will provide sufficient information so that a decision can be made as to the possible in-vivo significance of such a reaction to the induction of cancer. To accomplish these objectives the reaction of nitrosobenzene with selected analogs of "active acetaldehyde" will be investigated. This will be followed by an investigation of similar reactions with other nitroso compounds, including known carcinogens. Finally a kinetic analysis of the reaction and use of enzymes containing thiamine as a cofactor will be investigated.